In recent years, mankind has become increasingly aware of damage to the environment caused by on-site dumping of waste products which are often contaminated with harmful chemicals and other agents. As a consequence, regulations have been introduced by various regulatory authorities to forbid the dumping of waste products at locations other than controlled waste disposal sites.
Historically, in the natural gas well drilling and production field, it has been customary for companies drilling the gas wells and companies operating the gas wells to simply dump waste water, which is typically produced in a natural gas well, onto the ground adjacent the gas well. Regulations have recently been enacted which no longer permit such disposal. It has therefore become necessary to utilize water tank trucks to visit gas well sites on a frequent basis to collect the water and haul it away to a sanctioned water disposal site. This has become a very costly procedure. One way to reduce such expenses is to reduce the volume of water that is collected in a separator and tank of a gas producing well. The inventors have determined a strong need for efficient trouble-free technology that can dramatically reduce the volume of water produced by the gas well at the gas well site. This in turn dramatically reduces the volume of water that must be hauled away by water tank truck, and reduces operating expenses.
Submerged combustion heating is a method whereby hot products of combustion are forced through a liquid or liquid-solid mixture to heat the liquid or liquid-solid mixture and evaporate water. A major advantage of this heating system is that the heat exchange occurs directly between the hot gaseous products of combustion and the liquid. Thus there is no solid interface that interferes with efficient heat exchange. In a submerged combustion system, the hot combustion products are generated by a 2800° F. flame which is typically fueled by a combination of air and natural gas. The air under positive pressure is usually generated by a positive displacement blower. The flame generates hot combustion gases which contact the liquid to be heated, but the flame itself does not normally come into contact with the liquid.
Submerged combustion heated liquids have an overall system efficiency of greater than 90%. Conventional hot water boiler indirect heating systems have an efficiency of about 80%. Immersion tube heating systems have an efficiency of about 70%.
In applications where separation of components by distillation or absorption is required, submerged combustion heating can be applied to generate liquid or liquid-solid temperatures up to about 195° F. This temperature approaches the boiling point of water, and is applicable to most industrial and domestic liquid or liquid-solids heating applications.
In addition to high performance efficiency, submerged combustion heating systems are advantageous because they maintain a uniform temperature throughout the liquid in which the submerged combustion is conducted. This is because the hot gaseous combustion products pass rapidly as bubbles through the liquid and keep the liquid in constant agitation, thereby distributing heat evenly. Submerged combustion heating systems are also suitable for heating contaminated liquids, or liquids with low medium or high solids contents. Expenses are usually lower than with other heating systems because the submerged combustion heating can be performed in a liquid holding tank which can operate at ambient pressures, thereby eliminating the need for pressurization. Unlike boiler heating applications, a certified operating engineer is not required to operate a submerged combustion heating system.
The following patents relate to submerged combustion heating systems:    1. U.S. Pat. No. 5,606,965, granted Mar. 4, 1997 entitled “Submerged Combustion System”;    2. U.S. Pat. No. 5,615,668, granted Apr. 1, 1997, entitled “Apparatus for Cooling Combustion Chamber in a Submerged Combustion Heating System”;    3. U.S. Pat. No. 5,636,623, granted Jun. 10, 1997, entitled “Method and Apparatus for Minimizing Turbulence in a Submerged Combustion System”;    4. U.S. Pat. No. 6,293,277 B1, granted Sep. 25, 2001, entitled “Sludge Treatment System Using Two-Stage Heat Recovery Submerged Combustion; and    5. U.S. Pat. No. 6,338,337 B1, granted Jan. 15, 2002, entitled “Two-Stage Heat Recovery for Submerged Combustion Heating System”.
The subject matter and contents of these five aforementioned U.S. patents insofar as they are relevant to the subject invention is incorporated herein by reference.
The inventors have determined a need for effective apparatus and methods for reducing the volume of water at gas well sites.